arm64: dts: qcom: sc7280-herobrine: Add nodes for onboard USB hub

Add nodes for the onboard USB hub on herobrine devices. Remove the
'always-on' property from the hub regulator, since the regulator
is now managed by the onboard_usb_hub driver.

This requires "CONFIG_USB_ONBOARD_HUB=y".

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220722093238.v24.2.I18481b296484eec47bdc292a31fa46fa8c655ca9@changeid